Data · dataset · 2026
The Madden-Julian Oscillation in CCSM4
Listed in National Center for Atmospheric Research
This study assesses the ability of the Community Climate System Model, version 4 (CCSM4) to represent the Madden-Julian oscillation (MJO), the dominant mode of intraseasonal variability in the tropical atmosphere.
Description
The U.S. Climate Variability and Predictability (CLIVAR) MJO Working Group's prescribed diagnostic tests are used to evaluate the model's mean state, variance, and wavenumber-frequency characteristics in a 20-yr simulation of the intraseasonal variability in zonal winds at 850 hPa (U850) and 200 hPa (U200), and outgoing longwave radiation (OLR).
Unlike its predecessor, CCSM4 reproduces a number of aspects of MJO behavior more realistically. The CCSM4 produces coherent, broadbanded, and energetic patterns in eastward-propagating intraseasonal zonal winds and OLR in the tropical Indian and Pacific Oceans that are generally consistent with MJO characteristics. Strong peaks occur in power spectra and coherence spectra with periods between 20 and 100 days and zonal wavenumbers between 1 and 3.
Read the rest (2 more)
Model MJOs, however, tend to be more broadbanded in frequency than in observations. Broad-scale patterns, as revealed in combined EOFs of U850, U200, and OLR, are remarkably consistent with observations and indicate that large-scale convergence-convection coupling occurs in the simulated MJO. Relations between MJO in the model and its concurrence with other climate states are also explored.
MJO activity (defined as the percentage of time the MJO index exceeds 1.5) is enhanced during El Niño events compared to La Niña events, both in the model and observations. MJO activity is increased during periods of anomalously strong negative meridional wind shear in the Asian monsoon region and also during strong negative Indian Ocean zonal mode states, in both the model and observations.
Links
Get the data
- Publisher page n2t.org/ark:/85065/d7mc90qb ↗
documentation · download · from data ucar edu
Where it is published
- data.ucar.edu /dataset/the-madden-julian-oscillation-in-ccsm4 ↗
National Center for Atmospheric Research dataset page
landing page · from data ucar edu
Catalogue records · 1
- CKAN API data.ucar.edu/api/3/action/package_show?id=efef43f5-decb-4a2e-b161-98e27f745… ↗
metadata API · from data ucar edu
Topics
- From keywords
- Earth & Environmental Science · Ocean & Atmospheric Science
- Inferred from text
- Simulation 75%
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| National Center for Atmospheric Research | efef43f5-decb-4a2e-b161-98e27f74556f | 9 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| concepts[field].local:field:earth-environmental | mapping · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| concepts[field].local:field:ocean-atmospheric | mapping · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| concepts[method].local:method:simulation | enrichment · data ucar edu | keyword-concept-rules@1.0.0 | title+description (75%) |
| created_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| description | source · data ucar edu | connector:data_ucar_edu@1.0.0 | /notes |
| publication_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 | |
| title | source · data ucar edu | connector:data_ucar_edu@1.0.0 | /title |
| updated_date | source · data ucar edu | connector:data_ucar_edu@1.0.0 |